Tachometer.



M. HOEFT.

TAUHOMETER.

APPLIGATION FILED SEPT. 7, 1910.

COLUMBIA PLANOERAPH co.. wAsmNa'roN. D. c.

M. HOEPT.

TAOEOMETER.

APPLICATION FILED snr'1.7, 1910.

Patented sept. 17,1912.'

4 SHEETS-SHEET 2.

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Ilm n| l r l 1||| n n I l n 41,421-1- f /J n Vi-; n n rv COLUMBIA PLANOGRAPH C0.. WASHINGTON. D. Gr-

M. HOEFT.

TAGHOMETBR.

APPLIOATION FILED sBPT. '1, 1910.

Patented Sept. .17, 1912.

4 SHEETS-SHEET 8.

CULUMBLA PLANOGIAPDI C0.. WASHINGNN. D. Cu

M. HOEFT.

TAOHOMETER.

APPLIGATION FILED SEPT. 7, 1910.

Patented Sept. 17,1912.

4 SHEETS-SHEET 4.

COLUMBIA PLANOGRAPH UNITED .sTATEs PATENT oEEioE.

MAX HOEET, or BERLIN, GERMANY.

A"iuioroiviETEE specifiton of Letters Patent.

Patented Sept. 17, 1912.

Application Vinea september 7, 1910. sentano. 580,857.

accumulator' (hereinafter called an accumu` lator) the outlet opening of which is aut-omatically opened more or less, according to the speed at which the pump is driven, so that the height of the piston in the accumulator will depend on, and will serve to indicate, said speed. In apparatus of this kind it has been found that the piston, on the speed decreasing, cannot retreat sulficiently quickly. Further, the valve by which the outlet is regulated is prevented, apparently owing to compression of the fluid, from returning with the necessary speed. In order to overcome these drawbacks of existing apparatus, one or more auxiliary openings are provided in the accumulator, which openings, according to the speed, are opened either for a longer or shorter time, or, as experience has shown to be better, more or less frequently.

On the drawing the invention is illustrated by way of example.

Figures 1 and 1a together represent a side elevation partly in section on line 1, l,-

Fig. 5 of the tachometer, the casing being shown entirely in section, Fig. 2, an elevation of the pawl gearing at the right end of Fig. 1, Fig. 3, a section on A-B in Fig. la, Fig. 4L, an end elevation the casing not being shown in Figs. 3 and 4. Fig. 5 is a section on line C-I) of Fig. 1, and on line C-D of Fig. la, and Fig. 6 is a plan of the lever for operating the main valve, and Fig. 7 is a detail horizontal section on 'line 7, 7, Fig. 4.

The pumps a are driven by the machine, vehicle, or the like, the speed of which has to be measured, through the agency of the spur wheels b, c and force the Huid contained in the casing I which incloses the whole apparatus through the passage al into the cylinder d, so that it acts on the piston e contained therein. Near the bottom end of the cylinder 0l is situated the main outlet f,

which corresponds more or less with an opening g of the valve L. The valve is moved by the piston e. `For this purpose the pistonis connected with a toothed rack z', which engages in the toothed wheel 7c fastened to the vspindle Z, to the ends of which are fastened the spring case m and cam disk n. The spring in the case m has the tendency to depress the piston and is wound up by the piston rising. Againstthe cam 'n is pressed by a spring 02 a roller n. which is at tached to the arm o secured on the spindle 0, so that the valve 7L is turned more or less accordingto the angular position of the cam 11.. On the speed decreasing, the liquid, as experience has shown, cannot escape quickly enough out of the cylinder d to enable the piston c to descend and turn the toothed wheel c in exact accordance with the fall of speed. Moreover the liquid also prevents the valve g1 from turning back even to the amount which will keep the roller n in contact with the cam n. This drawback is effectually overcome by providing the auxiliary valve p, which is opened periodically by the pawl t on the lever s striking against the arm u attached to the spindle of said valve. The lever s is oscillated by the tappet disk T on the shaft g, said shaft being driven by the spur-wheel o. By the tappets on the disk -r the lever s is moved in one direction, while it is returned by the spring s. A spring u closes the valve p as soon as the pawl z5 slips over the arm u. The area of the auxiliary valve opening is much less than that of the principal valve, but suffices to give the piston and main valve the required relief when the speed falls.

Most fluids are influenced by changes of temperature, so that the height of the piston for a certain speed will be different at dif-y `.by the lever fw through a larger or smaller angle the effective valve-opening p is larger or smaller. In this way theinfluence of the temperature on the uid can be counter-acted.

What I claim and desire to secure `by Lct-V p p Vf taining lu1dfa pump 1n sald casing, a cyl- 'lnd'erl communicating ktherewith and haV- ters Patent of the United States is 1. A tachometer `comprising a pump, a" cylinder communicating therewith and `having a main outlet and an auxiliary outlet,l means adapted to regulatethe eective size Q of the main outlet according to the position of the piston in said cylinder?, andauto matic means adapted to continuously open A by mechanical connection with said box to and close said lauxiliary outlet. f`

2. A tachometer Vcomprising a pump.; a| 'cylinder communicating therewith and hav- .ing a main larger outlet opening andan 'auxiliary Vsmaller outlet opening,i a`V main valve adapted to control the larger outlet opening, an auxiliary valve adapted to control the smaller outlet opening, means adapt-- 'ed to open said main valve to ay greater Vor Gopiesrof this patent may be 4obtained for adapted to open and close said auxiliary valve. Y .Y Y

Y 3.1A tacho'meter comprising a casing coning a largeor main 'outlet-opening, a small auxiliaryoutlet-opening, means adapted to regulate the effective size of the main outlet-opening according to the position of the piston in Said-cylinder, an expansion-box located in said casing, and a Valve adapted be adjusted by the same according to the temperature of the fluid in the casing.

In testimony whereof I have signed my name to this specification in the presence of two .subscribing witnesses.

MAX HOEFT.

Witnesses:

WOLDEMAR HAUPT, HENRY HASPER.

ve cen'ts each, lnyaddressing` the V Commissioner of iatents. Washington, D. C. 

